JP4574911B2

JP4574911B2 - Polyester-based hollow crimped fiber and method for producing the same

Info

Publication number: JP4574911B2
Application number: JP2001246978A
Authority: JP
Inventors: 信幸山本; 裕憲合田
Original assignee: Teijin Fibers Ltd
Current assignee: Teijin Fibers Ltd
Priority date: 2001-08-16
Filing date: 2001-08-16
Publication date: 2010-11-04
Anticipated expiration: 2021-08-16
Also published as: JP2003055838A

Description

【０００１】
【発明の属する技術分野】
本発明は、長手方向に連続する複数の中空部を有するポリエステル系中空捲縮繊維の製造方法に関する。
【０００２】
【従来の技術】
ポリエチレンテレフタレートに代表されるポリエステル系繊維は機械的強度、耐薬品性、耐熱性などに優れるため、衣料用途や産業用途などを主体に広く使用されている。なかでも、詰綿、キルトのような、保温性および嵩高性が要求される用途では、繊維を中空化するとともに繊維に三次元的な捲縮を付与する方法が一般的に採用されている。本用途においては、繊維の保温性および嵩高性を高めるために繊維横断面における中空部の総面積の全繊維横断面積に占める割合（以下中空率と称する）を大きくする試みがなされている。しかし、大きな中空率を持つ中空繊維は、繊維の加工中あるいは製品として使用中に、潰れ易く、その繊維の保温性および嵩高性は滅失してしまうことが多い。この中空潰れを防ぐために、米国特許第５１０４７２５号に開示されているように繊維断面に複数の中空部分を持つ、多孔中空ポリエステル繊維が提案されている。しかし、３個以上の中空部分を有する多孔中空繊維を溶融紡糸方法で得ようとすると、吐出されたポリマー糸条流をすばやく冷却しなければならないので、紡糸口金から吐出前のポリマー温度を低く設定したり、紡糸口金面直下で繊維を急冷したりしなければならない。このような溶融紡糸条件では紡糸口金面温度が下がり、ポリマー吐出不良や糸切れが頻発する。また、このようにして製造された多孔中空繊維の中空率は高々２０％にとどまっていた。
【０００３】
また、芳香族ポリエステル系繊維に三次元捲縮繊維を付与する方法としては、例えば特公昭３８−７５１１号公報、特公昭４４−２０４９７号公報、特公昭４５−３６３３０号公報等に開示されているような、紡糸口金から吐出された直後のポリマー糸条流を断面方向に非対称に冷却（以下異方冷却と称する）することにより、該糸条に断面異方性を生じさせ、紡糸引き取りし、延伸後弛緩熱処理することにより三次元捲縮を発現させる方法等が知られている。しかし、いずれの方法で製造された芳香族ポリエステル繊維でも、三次元捲縮性は有しているものの、３個以上の中空部分を有する多孔中空繊維で中空率が２０％を超えるような繊維は存在しない。このように、未だ、充分な保温性能を有しかつ三次元捲縮を有する芳香族ポリエステル系繊維は提供されていない。
【０００４】
【発明が解決しようとする課題】
本発明の目的は、充分な保温性能を有しかつ三次元捲縮を有する芳香族ポリエステル系繊維を安定して生産する方法を提供することにある。
【０００５】
【課題を解決するための手段】
本発明者らは、上記課題を解決すべく鋭意検討した結果、繊維軸方向に連続する中空部が３〜８個存在する多孔中空繊維であって、横断面における中空部の総面積が横断面の外周部に囲まれた面積に対して２５〜６０％であり、かつ断面異方性に基づく三次元捲縮を有するポリエステル系中空捲縮繊維を製造する方法であって、芳香族ポリエステルにポリ乳酸を主成分とするポリエステルを重量基準で１〜５％の割合で混合後溶融あるいは溶融後混合し、多孔中空断面を形成し得る吐出孔を有する紡糸口金より吐出し、０．４〜１．０ｍ／秒の流速の冷却気流を吐出ポリマー糸条流の片側から該ポリマー糸条流の進行方向に垂直な面に対し＋２０〜−２０度の角度の範囲内で吹き当てた後、未延伸繊維として引き取り、次いで該未延伸繊維を延伸後、弛緩熱処理するポリエステル系中空捲縮繊維の製造方法を見出した。
【０００６】
【発明の実施の形態】
以下本発明を詳細に説明する。本発明の芳香族ポリエステルとは、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリトリメチレンテレフタレート系のホモポリエステル、コポリエステル又はこれらのポリエステルに第３成分を混合したポリエステルからなるものであり、特に繰返し単位の９０モル％以上がエチレンテレフタレート単位であるポリエステルが好ましく、ホモポリエチレンテレフタレートが最も好ましい。１０モル％以下で共重合し得る共重合成分としては、酸成分としてイソフタル酸、５−ナトリウムスルホイソフタル酸、ジフェニルジカルボン酸、ナフタレンジカルボン酸等の芳香族ジカルボン酸、しゅう酸、アジピン酸、セバチン酸、ドデカン二酸等の脂肪族ジカルボン酸、Ｐ−オキシ安息香酸、Ｐ−βーヒドロキシエトキシ安息香酸等のオキシカルボン酸があげられ、またジオール成分としては、１，３−プロパンジオール、１，６−へキサンジオール、ネオペンチルグリコール等の脂肪族ジオール、１，４−ビス（β−ヒドロキシエトキシ）ベンゼン等の芳香族ジオール、ポリエチレングリコール、ポリブチレングリコール等のポリアルキレングリコール等があげられる。なおこれら第３成分は、単独で共重合させても２種以上を同時に共重合させてもよい。
【０００７】
また、必要に応じて、各種の添加剤、例えば、艶消し剤、熱安定剤、消泡剤、整色剤、難燃剤、酸化防止剤、紫外線吸収剤、赤外線吸収剤、蛍光増白剤、着色顔料などを必要に応じて添加することができる。
【０００８】
本発明の芳香族ポリエステル系中空捲縮繊維は、図１（ａ）〜（ｂ）に示す様な繊維断面形状をなしており、繊維軸方向に連続する中空部（図１の１）が３〜８個存在する多孔中空繊維であって、中空率が２５〜６０％であり、かつ断面異方性に基づく三次元捲縮を有していなければならない。
【０００９】
繊維軸方向に連続する中空部が１〜２個の場合は、中空部分が繊維の加工中あるいは製品として使用中に潰れ易く、該繊維を綿として使用する時、保温性が発現せず、また嵩高性も大幅に低減する。中空部が８個を超える場合は、中空率を２５％以上に上げることが困難であり、充分な保温性を確保することができない。なお、中空部の数は４〜７個が、嵩高性と保温性とのバランス上、より好ましい。
【００１０】
中空率が２５％未満の場合は、該繊維を綿として使用する時、保温性が発現せず、また嵩高性も大幅に低減する。中空率が６０％を超える場合は、繊維横断面内に支えを持つ多孔中空繊維の場合でも、外力により中空潰れを生じ易くなり、保温性が発現せず、また嵩高性も大幅に低減する。また、カード工程での通過性が低下する。なお、より好ましい中空率の範囲は３０〜４０％である。
【００１１】
さらに、本発明の芳香族ポリエステル系中空捲縮繊維は断面異方性に基づく三次元捲縮を有していなければならない。このような三次元捲縮を有する中空繊維は、綿または開繊したトウの状態で、優れた保温性に加えて、反発性に富み、回復性に富んだ（すなわちヘタリの少ない）嵩高性能を発揮する。このような嵩高性能はＪＩＳ−Ｌ１０９７に記載の方法で圧縮弾性（圧縮率および回復率）および嵩高性（比容積）を測定することによって定量的に評価することができる。
【００１２】
本発明の芳香族ポリエステル系中空捲縮繊維は、例えば、以下の方法により製造することができる。
本発明においては、紡糸口金より吐出されるポリマー糸条流は、重量基準で１〜５％、さらに好ましくは２〜３重量％の範囲のポリ乳酸を主成分とするポリエステルを含んだ状態でなければならない。ここで、ポリ乳酸を主成分とするポリエステルとは、乳酸を主たる繰り返し単位とするポリエステルをいい、Ｌ−乳酸及び／又はＤ−乳酸成分が５０重量％以上の重合体であり、ポリＬ−乳酸ホモポリマー、ポリＤ−乳酸ホモポリマー、Ｌ−乳酸／Ｄ−乳酸共重合ポリマー及びそれらに５０％以下の第２又は第３成分を共重合及び／又は混合した物を包含する。共重合成分としては、例えばエチレングリコール、ブタンジオール、ヘキサンジオール、オクタンジオール、デカンジオールなどのジオール、コハク酸、アジピン酸、セバシン酸などのジカルボン酸、ヒドロキシアルキルカルボン酸、ピバロラクトン、カプロラクトンなどの脂肪族ラクトン、ポリエチレングリコールなどが挙げられる。なお、分子量は１０００００〜３０００００の範囲ものが好ましく挙げられる。
【００１３】
本発明の基質ポリマーである芳香族ポリエステルとポリ乳酸を主成分とするポリエステル（以下ポリマーＢと称する）との混合は、溶融工程以前でお互いに固体の状態で実施しても良いし、おのおの別途に溶融した後溶融体同士を合流させても良い。
【００１４】
このようにしてポリマーＢを含み、例えば、図２（ａ）〜（ｂ）に示すような形状の吐出孔を有する紡糸口金より吐出されたポリマー糸条流に対し、０．４〜１．０ｍ／秒の流速の冷却気流を吐出ポリマー糸条流の片側から、該ポリマー糸条流の進行方向に垂直な面に対し＋２０〜−２０度の角度の範囲内で吹き当てると、冷却・固化後のポリエステル繊維断面に顕著な構造異方性が生じ、熱処理後優れた三次元捲縮が発現する。また、驚くべきことに、ポリマーＢを使用した場合、２５％以上の中空率を有する繊維断面を安定して作り出すことができる。
【００１５】
ポリマーＢの混合割合が５％を超えると、紡糸時曳糸性が悪くなり断糸が多発する。ポリマーＢの混合割合が１％未満の場合は、中空率を２５％以上とすることができず、また異方冷却効果も充分に付与されない。
【００１６】
従来、芳香族ポリエステルを単独で紡糸し、繊維に十分な断面異方性を持たせるには、例えばポリエチレンテレフタレート繊維の場合、１．０ｍ／秒以上の流速を有する冷却気流を糸条の片側から吹き当てる必要があり、紡糸口金面の温度低下に伴う、曳糸性不良現象が発生していた。一方、ポリマーＢを使用した本発明の方法においては、０．４ｍ／秒以上の流速で冷却風を吹き当てれば十分な異方冷却効果が付与される。冷却風の流速が１．０ｍ／秒を超えると、紡糸口金面の温度低下に伴う、曳糸性不良現象が発生するので避けねばならない。また、冷却風の流速を０．５〜０．８ｍ／秒とすることにより、より好ましい状態で紡糸運転を実施することができる。
【００１７】
冷却気流は、吐出ポリマー糸条流の進行方向に垂直な面に対し＋２０〜−２０度の角度で吐出ポリマー糸条流に吹き当てなければならない。冷却気流を吹き当てる角度が吐出ポリマー糸条流の進行方向に垂直な面に対し＋２０〜−２０度を超えると、ポリマー糸条流の走行状態が乱れて紡糸断糸が多発し、また異方冷却効果も低減する。なお、ポリマー糸条流の進行方向にほぼ垂直に冷却風を吹き当てるのがより好ましい。
【００１８】
冷却・固化後引き取りされた未延伸繊維は、次いで温水浴等を備えた延伸装置で延伸し、繊維間の拘束を少なくした状態で弛緩熱処理した後、所定長に切断することにより、スパイラル状の三次元捲縮を有するポリエステル系中空繊維が得られる。
【００１９】
また、本発明のポリエステル系中空捲縮繊維は、場合によっては、短繊維に切断することなく、トウ状態のままで開繊し、不織布、布団用途等に使用しても良い。
【００２０】
【実施例】
次に、実施例により本発明を具体的に説明する。なお、実施例における各項目は次の方法で測定した。
（１）固有粘度
オルソクロロフェノールを溶媒として、３５℃の温度でウベローデ粘度管にて測定した。
（２）中空率
繊維の切断面を写真に撮り、２０個の断面について中空部と単繊維断面との面積を測定し、単繊維断面の面積に対する中空部の面積百分率（％）の平均値を中空率とした。
（３）繊度、繊維長、捲縮数、捲縮率
ＪＩＳ−Ｌ１０１５に記載の方法に準拠して測定した。
（４）保温性
得られた短繊維をカードに通してウェブを作り、ＪＩＳ−Ａ１４１２に記載の平板比較法に準拠して、密度０．０１ｇ／ｃｍ³のカードウェブの熱伝導率（Ｗ／（ｍ・Ｋ））を測定することにより判定した。熱伝導率が小さいほど、保温性が良好であることを示す。
（５）嵩高性能
得られた短繊維をカードに通してウェブを作り、ＪＩＳ−Ｌ１０９７に記載の嵩高性能（比容積、圧縮率および回復率）を測定した。
（６）カード通過性
ドッファーの表面速度３５ｍ／分、紡出ウェブの目付が５０ｇ／ｍ²となる条件でカードにかけ、１時間運転を行った際のカード通過状態を観察し、次に示す基準で判定した。
レベル１：カードを通過し、シリンダー等への繊維捲き付きがない。
レベル２：カードを通過するが、シリンダー等へ繊維捲き付きが見られる。
レベル３：カードからウェブが出てこなくなる。
（７）紡糸安定性
１０日間紡糸機を運転し、発生した糸切れ回数を記録した。
【００２１】
［実施例１］
固有粘度０．６４のポリエチレンテレフタレートチップに、ポリマーＢとして（株）島津製作所製の「ラクティ＃９０２０」チップ（ポリ乳酸、重量平均分子量２０００００、融点１７５℃）を３重量％均一に混合した混合体を、１６０℃で７時間乾燥した後、２９０℃で溶融し、図２（ａ）に示す形状の吐出孔を１５０個穿設した紡糸口金より吐出量４８０ｇ／分で吐出し、吹き出し口の上端がポリマー吐出面から２０ｍｍとなるように設置された長さ２０ｃｍ、幅２０ｃｍの冷却空気吹き出し口から２５℃の冷却空気を０．８ｍ／秒の流速でポリマー流の片側から糸条の進行方向に垂直な角度で吹き当て、１２００ｍ／分の速度で紡糸引き取りし未延伸ポリエチレンテレフタレート繊維を得た。
【００２２】
次いで、得られた未延伸繊維を５０万デシテックスのトウに引き揃えた後、第１段延伸温度７０℃、第２段延伸温度９０℃で２．４６倍に温水延伸し、６４ｍｍの繊維長にカットした後、１３５℃で弛緩熱収縮処理を施して、図１（ａ）に示すような繊維断面をもつ、繊度１２．４デシテックス、中空率３８％、捲縮数９．３山／２５ｍｍおよび捲縮率３０．７％のポリエチレンテレフタレート中空捲縮繊維を得た。
得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００２３】
［比較例１］
固有粘度０．６４のポリエチレンテレフタレートチップを、１６０℃で７時間乾燥した後、２９０℃で溶融し、図２（ａ）に示す形状の吐出孔を１５０個穿設した紡糸口金より吐出量４８０ｇ／分で吐出し、吹き出し口の上端がポリマー吐出面から２０ｍｍとなるように設置された長さ２０ｃｍ、幅２０ｃｍの冷却空気吹き出し口から２５℃の冷却空気を１．３ｍ／秒の流速でポリマー流の片側から糸条の進行方向に垂直な角度で吹き当て、１２００ｍ／分の速度で紡糸引き取りし未延伸ポリエチレンテレフタレート繊維を得た。
【００２４】
次いで、得られた未延伸繊維を５０万デシテックスのトウに引き揃えた後、第１段延伸温度７０℃、第２段延伸温度９０℃で２．４０倍に温水延伸し、６４ｍｍの繊維長にカットした後、１３５℃で弛緩熱収縮処理を施して、図１（ａ）に示すような繊維断面をもつ、繊度１２．３デシテックス、捲縮数８．５山／２５ｍｍおよび捲縮率２８．６％のポリエチレンテレフタレート中空捲縮繊維を得た。
得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００２５】
［実施例２］
ポリマーＢの含有率を１．０重量％とした他は、実施例１と同一の製法によって、図１（ａ）に示すような繊維断面をもつ、繊度１２．５デシテックス、中空率３０％、捲縮数９．４山／２５ｍｍおよび捲縮率２９．４％のポリエチレンテレフタレート中空捲縮繊維を得た。得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００２６】
［実施例３］
ポリマーＢの含有率を５．０重量％とした他は、実施例１と同一の製法によって、図１（ａ）に示すような繊維断面をもつ、繊度１２．５デシテックス、中空率３５％、捲縮数８．９山／２５ｍｍおよび捲縮率３２．２％のポリエチレンテレフタレート中空捲縮繊維を得た。得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００２７】
［実施例４］
図２（ｂ）に示す形状の吐出孔を１５０個穿設した紡糸口金より吐出量４８０ｇ／分で吐出した他は、実施例１と同一の製法によって、図１（ｂ）に示すような繊維断面をもつ、繊度１２．３デシテックス、中空率２７％、捲縮数８．９山／２５ｍｍおよび捲縮率２９．３％のポリエチレンテレフタレート中空捲縮繊維を得た。得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００２８】
［比較例２］
図２（ｃ）に示す形状の吐出孔を１５０個穿設した紡糸口金より吐出量４８０ｇ／分で吐出した他は、実施例１と同一の製法によって、図１（ｃ）に示すような繊維断面をもつ、繊度１２．５デシテックス、中空率１８％、捲縮数６．３山／２５ｍｍおよび捲縮率１８．２％のポリエチレンテレフタレート中空捲縮繊維を得た。得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００２９】
［実施例５］
冷却空気を１．０ｍ／秒の流速でポリマー流の片側から糸条の進行方向に垂直な角度で吹き当てた他は、実施例３と同一の製法によって、図１（ａ）に示すような繊維断面をもつ、繊度１２．４デシテックス、中空率５５％、捲縮数８．９山／２５ｍｍおよび捲縮率３１．５％のポリエチレンテレフタレート中空捲縮繊維を得た。得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００３０】
［比較例３］
ポリマーＢの含有率を６．０重量％とした他は、実施例５と同一の製法によって、図１（ａ）に示すような繊維断面をもつ、繊度１２．５デシテックス、中空率６５％、捲縮数１１．４山／２５ｍｍおよび捲縮率３２．３％のポリエチレンテレフタレート中空捲縮繊維を得た。得られた繊維をカードに通してウェブを作りその保温性能と嵩高性能を測定した。実施結果をまとめて表１に示す。
【００３１】
【表１】

【００３２】
【発明の効果】
本発明は、嵩高性に富み、ヘタリが少なく、かつ保温性に優れている、高中空率をもつポリエステル系多孔中空３次元捲縮繊維を提供するものであり、同時に、紡糸時の糸切れの少ない工程安定性に優れた、高中空率多孔中空３次元捲縮繊維の製造方法を提供する。
【図面の簡単な説明】
【図１】（ａ）〜（ｂ）は本発明のポリエステル系中空捲縮繊維横断面を説明するための模式図。（ｃ）は比較例２のポリエステル系中空捲縮繊維横断面を説明するための模式図。
【図２】（ａ）〜（ｂ）は本発明で用いられる紡糸口金の吐出孔形状の実施態様例を示した模式図。（ｃ）は比較例２で用いられる紡糸口金の吐出孔形状の実施態様例を示した模式図。
【符号の説明】
１：繊維断面中空部
２：紡糸口金吐出孔開口部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polyester-based hollow crimped fiber having a plurality of hollow portions continuous in the longitudinal direction.
[0002]
[Prior art]
Polyester fibers typified by polyethylene terephthalate are excellent in mechanical strength, chemical resistance, heat resistance, etc., and are therefore widely used mainly for clothing and industrial applications. In particular, in applications where heat retention and bulkiness are required such as stuffed cotton and quilt, a method of hollowing the fiber and imparting a three-dimensional crimp to the fiber is generally employed. In this application, an attempt has been made to increase the ratio of the total area of the hollow portion in the fiber cross section to the total fiber cross-sectional area (hereinafter referred to as the hollow ratio) in order to improve the heat retention and bulkiness of the fiber. However, hollow fibers having a large hollow ratio are easily crushed during fiber processing or use as a product, and the heat retention and bulkiness of the fibers are often lost. In order to prevent this hollow crushing, a porous hollow polyester fiber having a plurality of hollow portions in the fiber cross section as disclosed in US Pat. No. 5,104,725 has been proposed. However, when trying to obtain porous hollow fibers having three or more hollow parts by the melt spinning method, the discharged polymer yarn stream must be cooled quickly, so the polymer temperature before discharging from the spinneret is set low. Or rapidly cooling the fiber directly under the spinneret surface. Under such melt spinning conditions, the spinneret surface temperature is lowered, and polymer discharge failure and yarn breakage frequently occur. Moreover, the hollowness of the porous hollow fiber produced in this way was at most 20%.
[0003]
Also, methods for imparting three-dimensional crimped fibers to aromatic polyester fibers are disclosed in, for example, Japanese Patent Publication No. 38-7511, Japanese Patent Publication No. 44-20497, Japanese Patent Publication No. 45-36330. By asymmetrically cooling the polymer yarn flow immediately after being discharged from the spinneret in the cross-sectional direction (hereinafter referred to as anisotropic cooling), the cross-section anisotropy is produced in the yarn, and the yarn is taken up. A method for expressing a three-dimensional crimp by performing a relaxation heat treatment after stretching is known. However, although the aromatic polyester fiber manufactured by any method has three-dimensional crimpability, a fiber having a hollow ratio of more than 20% with a porous hollow fiber having three or more hollow portions is not used. not exist. As described above, an aromatic polyester fiber having sufficient heat retention performance and three-dimensional crimp has not yet been provided.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for stably producing an aromatic polyester fiber having sufficient heat retention performance and having three-dimensional crimps.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are porous hollow fibers having 3 to 8 hollow portions continuous in the fiber axis direction, and the total area of the hollow portions in the cross section is the cross section. Is a method for producing a polyester-based hollow crimped fiber having a three-dimensional crimp based on the cross-sectional anisotropy and having an area surrounded by the outer peripheral portion of A polyester containing lactic acid as a main component is mixed and melted or mixed after melting at a ratio of 1 to 5% on a weight basis, and discharged from a spinneret having discharge holes capable of forming a porous hollow cross section. A non-stretched fiber after spraying a cooling airflow at a flow rate of 0 m / sec from one side of the discharged polymer yarn flow within an angle range of +20 to −20 degrees with respect to a plane perpendicular to the direction of travel of the polymer yarn flow And then the unstretched fiber Shingo, found a method for producing a polyester-based hollow crimped fibers to relax heat treatment.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. The aromatic polyester of the present invention is composed of polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate homopolyester, copolyester or polyester obtained by mixing a third component with these polyesters. Polyesters having at least mol% ethylene terephthalate units are preferred, and homopolyethylene terephthalate is most preferred. Examples of copolymer components that can be copolymerized at 10 mol% or less include aromatic dicarboxylic acids such as isophthalic acid, 5-sodium sulfoisophthalic acid, diphenyldicarboxylic acid, and naphthalenedicarboxylic acid, oxalic acid, adipic acid, and sebacic acid. , Aliphatic dicarboxylic acids such as dodecanedioic acid, oxycarboxylic acids such as P-oxybenzoic acid and P-β-hydroxyethoxybenzoic acid, and diol components include 1,3-propanediol, 1,6 Examples thereof include aliphatic diols such as hexanediol and neopentyl glycol, aromatic diols such as 1,4-bis (β-hydroxyethoxy) benzene, and polyalkylene glycols such as polyethylene glycol and polybutylene glycol. These third components may be copolymerized alone or two or more of them may be copolymerized simultaneously.
[0007]
If necessary, various additives such as matting agents, heat stabilizers, antifoaming agents, color modifiers, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, fluorescent whitening agents, A coloring pigment or the like can be added as necessary.
[0008]
The aromatic polyester-based hollow crimped fiber of the present invention has a fiber cross-sectional shape as shown in FIGS. 1A to 1B, and 3 hollow portions (1 in FIG. 1) continuous in the fiber axis direction. It should be ˜8 porous hollow fibers with a hollowness of 25-60% and a three-dimensional crimp based on cross-sectional anisotropy.
[0009]
When the number of hollow portions continuous in the fiber axis direction is 1 to 2, the hollow portion is easily crushed during processing of the fiber or during use as a product, and when the fiber is used as cotton, heat retention is not expressed. Bulkiness is also greatly reduced. When the number of hollow portions exceeds 8, it is difficult to increase the hollow ratio to 25% or more, and sufficient heat retention cannot be ensured. In addition, the number of hollow portions is more preferably 4 to 7 in terms of the balance between bulkiness and heat retention.
[0010]
When the hollow ratio is less than 25%, when the fiber is used as cotton, heat retention is not exhibited, and bulkiness is greatly reduced. When the hollow ratio exceeds 60%, even in the case of a porous hollow fiber having a support in the fiber cross section, hollow crushing is liable to occur due to an external force, heat insulation is not exhibited, and bulkiness is greatly reduced. Moreover, the passability in a card process falls. In addition, the range of a more preferable hollow ratio is 30 to 40%.
[0011]
Furthermore, the aromatic polyester-based hollow crimped fiber of the present invention must have a three-dimensional crimp based on cross-sectional anisotropy. The hollow fiber having such three-dimensional crimps is not only excellent in heat retention, but also has high resilience and recoverability (that is, less stagnation) in the state of cotton or opened tow. Demonstrate. Such bulk high performance can be quantitatively evaluated by measuring compression elasticity (compression rate and recovery rate) and bulkiness (specific volume) by the method described in JIS-L1097.
[0012]
The aromatic polyester hollow crimped fiber of the present invention can be produced, for example, by the following method.
In the present invention, the polymer yarn flow discharged from the spinneret must contain a polyester based on polylactic acid in the range of 1 to 5% by weight, more preferably 2 to 3% by weight. I must. Here, the polyester having polylactic acid as a main component means a polyester having lactic acid as a main repeating unit, and is a polymer having an L-lactic acid and / or D-lactic acid component of 50% by weight or more. It includes a homopolymer, a poly D-lactic acid homopolymer, an L-lactic acid / D-lactic acid copolymer, and a product obtained by copolymerizing and / or mixing 50% or less of the second or third component. Examples of the copolymer component include diols such as ethylene glycol, butanediol, hexanediol, octanediol, and decanediol, dicarboxylic acids such as succinic acid, adipic acid, and sebacic acid, and aliphatics such as hydroxyalkylcarboxylic acid, pivalolactone, and caprolactone. Examples include lactone and polyethylene glycol. The molecular weight is preferably in the range of 100,000 to 300,000.
[0013]
The mixing of the aromatic polyester, which is the substrate polymer of the present invention, and the polyester mainly composed of polylactic acid (hereinafter referred to as polymer B) may be carried out in a solid state before the melting step, or separately. The melts may be joined together after being melted.
[0014]
Thus, the polymer yarn flow containing the polymer B, for example, 0.4 to 1.0 m with respect to the polymer yarn flow discharged from the spinneret having the discharge holes having the shapes as shown in FIGS. After cooling and solidification, a cooling airflow with a flow rate of / sec is blown from one side of the discharged polymer yarn flow within an angle range of +20 to -20 degrees with respect to a surface perpendicular to the direction of travel of the polymer yarn flow. Remarkable structural anisotropy occurs in the cross section of the polyester fiber, and excellent three-dimensional crimp is developed after the heat treatment. Surprisingly, when the polymer B is used, a fiber cross section having a hollowness of 25% or more can be stably produced.
[0015]
When the mixing ratio of the polymer B exceeds 5%, the spinnability becomes poor at the time of spinning, and the yarn breakage occurs frequently. When the mixing ratio of the polymer B is less than 1%, the hollow ratio cannot be made 25% or more, and the anisotropic cooling effect is not sufficiently imparted.
[0016]
Conventionally, in order to spin an aromatic polyester alone and give the fiber sufficient cross-sectional anisotropy, for example, in the case of polyethylene terephthalate fiber, a cooling air flow having a flow velocity of 1.0 m / sec or more is applied from one side of the yarn. It was necessary to spray, and a spinnability defect phenomenon occurred with a decrease in the temperature of the spinneret surface. On the other hand, in the method of the present invention using the polymer B, a sufficient anisotropic cooling effect is imparted if the cooling air is blown at a flow rate of 0.4 m / second or more. If the flow velocity of the cooling air exceeds 1.0 m / sec, a spinnability defect phenomenon occurs due to a decrease in the temperature of the spinneret surface, which must be avoided. In addition, the spinning operation can be performed in a more preferable state by setting the flow rate of the cooling air to 0.5 to 0.8 m / second.
[0017]
The cooling air flow must be blown against the discharged polymer yarn flow at an angle of +20 to -20 degrees with respect to a plane perpendicular to the direction of travel of the discharged polymer yarn flow. If the angle at which the cooling airflow is blown exceeds +20 to -20 degrees with respect to the surface perpendicular to the direction of travel of the discharged polymer yarn flow, the running state of the polymer yarn flow is disturbed, and spun yarns occur frequently and are anisotropic. The cooling effect is also reduced. More preferably, the cooling air is blown almost perpendicularly to the direction of travel of the polymer yarn flow.
[0018]
The unstretched fiber taken after cooling and solidification is then stretched by a stretching apparatus equipped with a hot water bath or the like, and after relaxing heat treatment in a state in which the constraint between the fibers is reduced, the unstretched fiber is cut into a predetermined length to form a spiral shape. A polyester-based hollow fiber having a three-dimensional crimp is obtained.
[0019]
In addition, the polyester-based hollow crimped fiber of the present invention may be opened in a tow state without being cut into short fibers, and used for nonwoven fabrics, futon applications, and the like.
[0020]
【Example】
Next, the present invention will be described specifically by way of examples. In addition, each item in an Example was measured with the following method.
(1) Intrinsic viscosity Measured with an Ubbelohde viscosity tube at a temperature of 35 ° C. using orthochlorophenol as a solvent.
(2) Take a photograph of the cut surface of the hollow fiber, measure the area of the hollow part and the single fiber cross section for 20 cross sections, and calculate the average value of the area percentage (%) of the hollow part with respect to the area of the single fiber cross section The hollow ratio was used.
(3) Fineness, fiber length, number of crimps, crimp ratio Measured according to the method described in JIS-L1015.
(4) create a web through a short fiber obtained warmth to the card, in compliance with the flat plate comparison method described in JIS-1412, the thermal conductivity of the density of 0.01 g / cm ³ of the card web (W / (M · K)) was measured. It shows that heat retention is so favorable that heat conductivity is small.
(5) Bulk high performance The obtained short fiber was passed through a card to make a web, and the bulk high performance (specific volume, compressibility and recovery rate) described in JIS-L1097 was measured.
(6) A card passing doffer is surfaced at 35 m / min and the basis weight of the spinning web is 50 g / m ^2. Judged by.
Level 1: Passes through the card and there is no fiber sticking to the cylinder.
Level 2: Passes through the card, but fiber sticking is seen on the cylinder.
Level 3: The web does not come out of the card.
(7) Spinning stability The spinning machine was operated for 10 days, and the number of yarn breaks that occurred was recorded.
[0021]
[Example 1]
A mixture of polyethylene terephthalate chip having an intrinsic viscosity of 0.64 and 3% by weight of “Lacty # 9020” chip (polylactic acid, weight average molecular weight 200000, melting point 175 ° C.) manufactured by Shimadzu Corporation as polymer B Was dried at 160 ° C. for 7 hours, melted at 290 ° C., and discharged at a discharge rate of 480 g / min from a spinneret having 150 discharge holes having the shape shown in FIG. From a cooling air outlet with a length of 20 cm and a width of 20 cm installed at a flow rate of 0.8 m / sec from one side of the polymer flow to the direction of yarn travel. It sprayed at a vertical angle and spun up at a speed of 1200 m / min to obtain unstretched polyethylene terephthalate fibers.
[0022]
Next, after the unstretched fibers obtained were aligned on 500,000 dtex tows, they were hot-water stretched 2.46 times at a first-stage stretching temperature of 70 ° C. and a second-stage stretching temperature of 90 ° C. to obtain a fiber length of 64 mm. After cutting, it was subjected to relaxation heat shrinkage treatment at 135 ° C., and had a fiber cross section as shown in FIG. 1 (a), a fineness of 12.4 dtex, a hollowness of 38%, a number of crimps of 9.3 peaks / 25 mm and A polyethylene terephthalate hollow crimped fiber having a crimp rate of 30.7% was obtained.
The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0023]
[Comparative Example 1]
A polyethylene terephthalate chip having an intrinsic viscosity of 0.64 is dried at 160 ° C. for 7 hours, melted at 290 ° C., and discharged from a spinneret having 150 discharge holes having the shape shown in FIG. The cooling air at 25 ° C. is fed at a flow rate of 1.3 m / sec from a cooling air blowing port having a length of 20 cm and a width of 20 cm installed so that the upper end of the blowing port is 20 mm from the polymer discharge surface. The fiber was sprayed from one side at an angle perpendicular to the traveling direction of the yarn, and the yarn was spun off at a speed of 1200 m / min to obtain unstretched polyethylene terephthalate fiber.
[0024]
Next, after the unstretched fibers obtained were aligned on a 500,000 dtex tow, they were hot-water stretched 2.40 times at a first-stage stretching temperature of 70 ° C. and a second-stage stretching temperature of 90 ° C. to obtain a fiber length of 64 mm. After cutting, it was subjected to relaxation heat shrinkage treatment at 135 ° C. to have a fiber cross section as shown in FIG. 1 (a), a fineness of 12.3 dtex, a crimp number of 8.5 crests / 25 mm, and a crimp rate of 28. 6% polyethylene terephthalate hollow crimped fiber was obtained.
The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0025]
[Example 2]
Except that the content ratio of the polymer B was 1.0% by weight, the same manufacturing method as in Example 1 had a fiber cross section as shown in FIG. 1 (a), a fineness of 12.5 dtex, a hollow ratio of 30%, A polyethylene terephthalate hollow crimp fiber having a crimp number of 9.4 peaks / 25 mm and a crimp rate of 29.4% was obtained. The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0026]
[Example 3]
Except that the content of the polymer B was 5.0% by weight, by the same production method as in Example 1, it had a fiber cross section as shown in FIG. 1 (a), a fineness of 12.5 dtex, a hollowness of 35%, A polyethylene terephthalate hollow crimp fiber having a crimp number of 8.9 peaks / 25 mm and a crimp rate of 32.2% was obtained. The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0027]
[Example 4]
A fiber as shown in FIG. 1 (b) is produced by the same manufacturing method as in Example 1 except that it is discharged from a spinneret having 150 discharge holes having the shape shown in FIG. 2 (b) at a discharge amount of 480 g / min. A polyethylene terephthalate hollow crimped fiber having a cross section, a fineness of 12.3 dtex, a hollowness of 27%, a crimped number of 8.9 peaks / 25 mm, and a crimped rate of 29.3% was obtained. The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0028]
[Comparative Example 2]
A fiber as shown in FIG. 1 (c) is produced by the same manufacturing method as in Example 1 except that it is discharged from a spinneret having 150 discharge holes having the shape shown in FIG. 2 (c) at a discharge rate of 480 g / min. A polyethylene terephthalate hollow crimped fiber having a cross-section, a fineness of 12.5 dtex, a hollowness of 18%, a crimp number of 6.3 threads / 25 mm, and a crimp of 18.2% was obtained. The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0029]
[Example 5]
As shown in FIG. 1A, the cooling air was blown at a flow rate of 1.0 m / sec from one side of the polymer stream at an angle perpendicular to the direction of yarn travel, by the same manufacturing method as in Example 3. A polyethylene terephthalate hollow crimped fiber having a fiber cross section and a fineness of 12.4 dtex, a hollowness of 55%, a crimped number of 8.9 peaks / 25 mm, and a crimping rate of 31.5% was obtained. The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0030]
[Comparative Example 3]
Except that the content of the polymer B was 6.0% by weight, by the same manufacturing method as in Example 5, the fiber cross section as shown in FIG. 1 (a), fineness of 12.5 dtex, hollow ratio of 65%, A polyethylene terephthalate hollow crimped fiber having a crimped number of 11.4 peaks / 25 mm and a crimping rate of 32.3% was obtained. The obtained fiber was passed through a card to make a web, and its heat retention performance and bulk performance were measured. The implementation results are summarized in Table 1.
[0031]
[Table 1]

[0032]
【The invention's effect】
The present invention provides a polyester-based porous hollow three-dimensional crimped fiber having a high hollow ratio, which is rich in bulk, has little settling, and has excellent heat retention properties. Provided is a method for producing a high hollow ratio porous hollow three-dimensional crimped fiber with excellent process stability.
[Brief description of the drawings]
1A to 1B are schematic views for explaining a cross section of a polyester-based hollow crimped fiber according to the present invention. (C) is a schematic diagram for demonstrating the polyester-type hollow crimped fiber cross section of the comparative example 2. FIG.
FIGS. 2A to 2B are schematic views showing an embodiment of a discharge hole shape of a spinneret used in the present invention. (C) is the schematic diagram which showed the embodiment example of the discharge hole shape of the spinneret used in the comparative example 2. FIG.
[Explanation of symbols]
1: Fiber cross-section hollow part 2: Spinneret discharge hole opening

Claims

It is a porous hollow fiber having 3 to 8 hollow portions continuous in the fiber axis direction, and the total area of the hollow portions in the cross section is 25 to 60% with respect to the area surrounded by the outer peripheral portion of the cross section And a method for producing a polyester-based hollow crimped fiber having a three-dimensional crimp based on cross-sectional anisotropy, and a ratio of 1 to 5% by weight of a polyester based on polylactic acid in an aromatic polyester The mixture is melted after mixing or mixed after melting and discharged from a spinneret having a discharge hole capable of forming a porous hollow cross section, and a cooling airflow with a flow rate of 0.4 to 1.0 m / sec is discharged from one side of the discharged polymer yarn flow. A polyester system in which the polymer yarn flow is blown within a range of an angle of +20 to −20 degrees with respect to a plane perpendicular to the traveling direction of the polymer yarn flow, and then taken out as an undrawn fiber, and then the undrawn fiber is drawn and then subjected to a relaxation heat treatment. Made of hollow crimped fiber Method.